OD is a new concept in managment theory and has evolved from the theories of human behaviorists. Its application in police organizations has been limited due to the theory's newness and to general resistance to change. As OD emerges as an accepted technique in modern organizations, criminal justice agencies must take a critical look at its major components and determine how best to apply them to a police organization. A review of the development of the police organization and its bureaucratization demonstrates that the traditional, 'mechanistic' police organization can no longer survive in the unstable environment in which it must exist. OD can be used to effect changes in an 'organic' organization which is highly flexible and responsive to changes in the environment. It is characterized by a long-range and sustained top management response to changes in the internal and external environment and by a process of initiating, creating, and confronting needed changes by using reflexive, self-analytic methods of applying the techniques of behavioral science for system improvement. OD's target is the organization as a total organic system, including its beliefs, values, and structures. Intervention programs are briefly reviewed, and the successful application of OD techniques at the San Francisco Police Department is described. Footnotes and a 48-item reference list are included.